It’s already a thing in Japan, Taiwan, Singapore and the Midwest, but will it catch on in America’s cities? Vertical farming, the art of growing crops on the sides of roofs or buildings, or even inside buildings in large cities, is the newest idea in growing local foods for urban dwellers.

There’s a long way to go before vertical farming really takes off. The amount of energy required to grow plants in indoor settings is pretty high.

“It’s such an appealing idea…that people picked up on it right away,” says Utah State University professor Bruce Bugbee. “The fundamental problem is that plants need a lot of light. If we’re going to do it inside, it will require burning a lot of fossil fuels.”

However, people who support the idea say that technology is improving to the point where vertical farming will soon be as common as flat-earth farming, especially as climate change and water supply problems make traditional farming more difficult.

AeroFarms, for example, operates a vertical farming operation in a warehouse in Newark, New Jersey, producing leafy greens and herbs. The company uses a closed-loop irrigation system and light-emitting diodes to minimize energy and water consumption. According to AeroFarms marketing director and co-founder Marc Oshima, using LEDs instead of sunlight means the growing season takes about two weeks rather than a couple of months, allowing for up to 30 harvests a year.

He also pointed out that the absence of pests helps to maximize growing and that the LEDs can emit colors that maximize growth, taste and nutrition.

Other vertical farms are taking a different approach, building structures specifically for their gardens. Swedish firm Plantagon International is working with real estate developers to construct purpose-built facilities. Plantagon plans to reduce energy costs by using heat thrown off by the artificial lighting to keep the buildings warm.

It’s hard to know for sure how much food comes from vertical farms, but the local-food movement seems to offer a market for this new business model. At this time it looks like the best bet for vertical farming is in the arena of crops like those AeroFarms is growing, since leafy greens are highly perishable and generally don’t do well when transported for long distances.

What do you think? Is vertical farming poised to be the next big thing, or is it more of a flash in the pan that is not sustainable in the long term? Share your thoughts in the comments!